A lack of iron in the diet weakens the immune response in the lungs

A lack of iron in the diet weakens the immune response in the lungs

Researchers at Columbia University have found that iron deficiency early in life can prevent immune cells in the lungs from producing a key protein that helps fight viral infections, even after iron levels are restored.

The results suggest that the immunological memory formed when iron levels are low may not provide sufficient protection against future exposures to the same viruses.

Iron deficiency, which disproportionately affects children, is one of the most common nutritional problems worldwide and has long been linked to an increased risk of viral infections and more serious illnesses. Our study sheds new light on one of the reasons for this.”

Thomas Connors, assistant professor of pediatrics, Columbia University Vagelos College of Physicians and Surgeons

The researchers focused on memory T cells – immune cells that help the body respond to previously encountered pathogens. To isolate the effects of iron, mice were fed a high-iron or low-iron diet and then infected with influenza.

The iron-deficient mice became more severely ill and showed reduced activation of T cells in the lungs than mice fed an iron-rich diet.

Mice with very low iron levels were able to produce normal-looking memory T cells in their lungs. However, further testing revealed that the ability of these memory cells to produce interferon gamma and tumor necrosis factor alpha - proteins that help immune cells recognize and fight infections - was impaired. The defect persisted even after iron levels were restored, suggesting that iron deficiency not only makes it more difficult to fight an infection, but could also have a lasting impact on how the immune system responds to future viral threats.

Nearly 10% of children in the United States suffer from iron deficiency, making it one of the most common nutritional problems in early life. Although routine screening for anemia - a late consequence of iron deficiency - helps identify children most in need of treatment, prevention remains essential. Since infancy and childhood are periods of rapid growth and development, which also include the maturation of the immune system, adequate iron intake is particularly important during these years.

“Our study highlights the importance of dietary iron for immune system development and future health,” says Connors. “It is important to ensure children eat a balanced diet and have regular checkups with their pediatrician.”

Connors' team plans to study the immune systems of children with iron deficiency to gain insight into how to strengthen the immune response. Researchers will also study the effects of iron deficiency on lung tissue to better understand why low iron levels are linked to chronic lung diseases such as asthma.

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